Relay with permanent magnets



Dec 1, 1970 w, sTE FF I 3,544,935

RELAY WITH PERMANENT MAGNETS Filed Nov. 1968 2 Sheets-Sheet 1 [fr/0r flr/j V Fig Dec. 1, 1970 w. STERFF 3,54

RELAY WITH PERMANENI MAGNETS Filed Nov. 6, 1968 2 Sheets-Sheet 2 Arum/5);

3,544,935 RELAY WITH PERMANENT MAGNETS Wilhelm Sterlf, Munich, Germany, assignor to Schaltbau Gesellschat't m.b.H., Munich, Germany, a corporation of Germany Filed Nov. 6, 1968, Ser. No. 773,927 Claims priority, application Germany, Nov. 8, 1967,

1,614,713; Sept. 19, 1968, 1,764,999

Int. Cl. H01f 7/08 US. Cl. 335-229 20 Claims ABSTRACT OF THE DISCLOSURE Three relay constructions, each having a coil-core structure, a pair of permanent magnets face each other with similar poles along the coil-core structure. A soft-iron member separates the magnets and serves as support for a rocking armature. The permanent magnets are disposed partially or completely on the other side of the coil-core structure relative to armature, the coil-core structure extending in between and being completely or partially enveloped by the permanent magnets, the enveloping being supplemented by the armature to the extent permitted by the rocking range.

The present invention relates to a relay construction using permanent magnetization to maintain particular positions of an armature, the armature controlling the positions and operating states of relay contacts. A particular construction for such relays is known in which a permanent magnet is positioned parallel to the coil-core structure and between the coil and the armature. The magnet has magnetization so that its two ends, as defined in axial direction, parallel to the coil-core structure provide similar poles, while in or near the center of the permanent magnet adjacent the center of the core-coil structure, the other pole of the permanent magnet faces away from the coil-core structure to serve as hearing and support for the rocking armature. The system is completed through pole shoes extending from the axial ends of the coil-core structure along the permanent magnet and toward the support bearing.

It is a particular characteristic of such a system that the magnetic flux of the permanent magnet runs partially through the pivot point of the armature. The flux is divided, most of it runs over that arm of the armature which abuts a pole shoe, but some flux runs from the other pole shoe, across the gap to and through the other arm of the rocking armature and also through the pivot point on the permanent magnet. Upon energization of the coil for actuating the relay, magnetic flux is concentrated at least to some extent through the pivot area of the rocking armature.

Such a system has basically two disadvantages. The particular construction of the permanent magnet requires that it is located as a whole between the coil-core structure and the armature. Moreover, the concentration of flux line in the pivot area as resulting from energization of the coil tends to demagnetize the permanent magnet, particularly in that portion serving as a bearing support for the rocking armature. As a consequence, the permanent magnet will be, to some extent, demagnetized or even remagnetized, and is, therefore, subjected to significant weakening during each energization.

It is a specific object of the invention to improve on relay constructions of this type to obviate these disadvantages. It is the particular object of the present invention to provide a compact relay construction using permanent magnets which are not subjected to such demagnetization.

United States Patent 3,544,935 Patented Dec. 1, 1970 According to one aspect of the present invention, in a preferred embodiment thereof, it is assumed that the coil-core structure to be employed has a generally axially directed orientation as far as direction of magnetization provided by the coil in the core is concerned. It is a specific feature of the present invention to employ a pair of permanent magnets, each at least partially embracing or enveloping the coil-core structure involving particularly different portions of the coil-core structure along the axis thereof. The two permanent magnets are separated and oriented so that similar magnetic poles face each other in axial direction and in about the middle of the coil-core structure. A soft-iron member separates the two magnets but is magnetically coupled to both of them at the similar poles which face each other. This soft-iron member is constructed in that it has, for example, an extremity serving as bearing support for a rocking armature. The permanent magnets thus envelope the coil-core structure from the side opposite to the armature, so that at least part of the magnets do not extend between armature and coil-core structure.

The armature has preferably two arms which extend symmetrically from the pivot point on the support. Essential is that the pivot area, or pivot line, is not formed directly by the permanent magnet but is merely magnetically coupled to them through soft-iron which can be magnetized as the operation requires. Any flux concentration in the bearing area at the pivot point is not continued to the vicinity of the permanent magnets. It is, moreover, a particular advantage that the two permanent magnets each can have symmetrical pole construction which is beneficial to obtain high pole strength for a given mass of magnetic material. The permanent magnets may have inner cylindrical bores for respectively receiving two ditferent, axially spaced portions of the coil-core structure. Alternatively, the permanent magnets may be constructed in the form of beds with, for example, semicircular cross sectional profile, in which the coil-core structure rests. In either case, a soft-iron member separates the two permanent magnets along the axis of the coil-core structure, but encloses the coil-core structure in ring-like fashion. The armature may have downwardly directed concave surface portions of matching profiles covering the portion of the coil-core structure as it extends upwardly from the permanent magnet beds to the extent permitted by the requirements for a rocking motion in an axial plane. A symmetrical rocking armature construction permits that always one arm of the armature covers almost completely the adjacent part of the exposed portion of the coil-core structure. The other arm extends angularly away from the other part of the coil-core structure, but only to the extent required to define a positive rocking range. The machining of a concave profile in the armature may be impractical so that the armature may be rather flat. 'In this case the permanent magnet beds are constructed to have, so to speak, tall side walls and the armature needs to cover the coil-core structure only to the extent of lid.

The constructions are completed through magnetic conducting means, such as two pole shoes, which extend respectively from the two axial ends of the coil-core structure and each in magnetically coupled relationship to the respective nonfacing poles of the two permanent magnets, toward the arms of the armature to operate as rocking stop and rocking angle limiting means, and for completing magnetic circuits through the armature, particularly as far as the energization from the coil of the coil-core structure is concerned while preventing the armature arms from sticking to any permanent magnet portion.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject mat- 3 ter which is regarded as the invention, it is believed that the invention, the objects and features of the invention and further objects, features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawing in which:

FIG. 1 illustrates somewhat schematically a plan view of a relay in accordance with the prior art and to be improved in accordance with the principles of the present invention;

FIG. 2 illustrates relay in accordance with first embodiment of the present invention, partially in plan view and partially in cross sectional view;

FIG. 3 illustrates a cross section through line 33 in FIG. 2;

FIG. 4 illustrates a perspective view of a relay in accordance with the preferred embodiment for practicing the present invention;

FIG. 5 illustrates a section view along lines 55 in FIG. 4; and

FIG. 6 illustrates a simplified form of the construction shown in FIG. 4 which is preferred over the latter as far as ease of manufacturing is concerned.

Proceeding now to the detailed description of the drawings, FIG. 1 illustrates a typical relay as it has been used before the invention. The relay includes a core 1 on which is wound an energizing coil 2. A permanent magnet 3 is positioned outside of and parallel to the coil-core structure. The permanent magnet 3 has magnetization in that particularly its two ends, considered in a direction parallel to the extension of core 1, have similar poles. The opposite pole is positioned in about a middle portion 4 of magnet 3 which is formed as a protrusion and serves as support and bearing of a swivel or rocking armature 5. The armature actuates contact pieces for circuit making and breaking. Two poles 6 and 7 are coupled magnetically to the two opposite ends of the core 1 in axial direction, to guide the magnetic flux into the vicinity of pole piece 4.

It is characteristic for the magnetizing system of this type that the magnetic flux of the permanent magnet runs through the pivot point of the rocking armature 5. In the illustrated position of the armature, magnetic flux runs essentially and predominantly through the pole shoe 7 from the north pole of magnet 3 where engaging pole shoe 7, into the rocking armature 5, where engaging pole shoe 7, through the pivot area to the south pole at bearing 4. Another magnetic flux path runs parallel thereto, from the permanent magnet through pole 6 toward the south pole at bearing 4. However, this parallel flux path encounters a considerably large air gap.

Upon providing an energizing current to coil 2, the resulting magnetic flux will at least partially run through the pivot point of the armature. Assuming, for example, that the energizing current has direction that a magnetic north pole is established at and in pole shoe 6, and a south pole at pole shoe 7, then the flux running through pole shoe 7 as reulting from energization of coil 2 compensates the magnetic flux which was produced by the permanent magnet in pole shoe 7 and in the adjacent portion of armature, to reduce the total flux in that path, preferably down to zero. Accordingly, there is little or no attraction for the armature 5 toward pole shoe 7. On the other hand, the Weak flux initially provided by the perma nent magnet in pole shoe 6 is now augmented by the flux produced by the energized coil-core structure so that in the left-hand portion of FIG. 1 there is a strong resulting flux tending to attract armature 5, and accordingly the armature snaps into the alternative position.

The device of this type has two essential disadvantages. First of all, the permanent magnet must be constructed so that its total volume is concentrated in a particular region; the entire permanent magnet extends betweeen the coil-core structure and the armature. Furthermore, the special configuration of its poles is, per se, disadvantageous and it should be noted that the resulting magnetic axis of this permanent magnet is ransver e o the mag-- netic axis of the coil-core structure. In general, this has resulted in disadvantageous dimension for the entire relay, as the overall height is relatively large.

The second disadvantage of this construction is to be seen in that the magnetic fiux, as provided by the coil, has to run through the pivot point of the armature and its support and bearing. For easy pivoting, the armature does not engage the support over an extensive area, but the physical contact should be confined at least approximately along a line. However, in most instances as far as actual positive, physical engagement is concerned, there will be only two points of contact, due to unevenness of the surfaces involved. There is, accordingly, a very high concentration of the magnetic flux in the vicinity of these points of contact.

As can readily be seen, the magnetic bias is symmetrical in relation to a plane of symmetry running through the plane of symmetry. As current flows through the coil 2, the resulting magnetic field superimposed upon the system is not symmetrical in relation to that plane, so that this field operates partially or in opposition and partially in support of the magnetic bias. Wherever the field from coil 2 tends to oppose the magnetic bias, the coil field actually tends to demagnetize the permanent magnet. In view of the concentration of flux lines in the pivot area on support and bearing 4, such demagnetization is sufficiently strong to succeed on a permanent basis.

Turning now to the construction shown in FIG. 2, there is illustrated a first embodiment of the present invention. The construction illustrated has again a core 8 enveloped by one or more energization coils collectively denoted by reference numeral 9. This coil-core structure is now enveloped by two permanent magnets 10 and 11. A ringshaped soft-iron body 12 envelopes the entire core-coil construction. Each of the elements 10, 11 and 12 has a cylindrical bore, and these bores are axially aligned to receive the coil-core structure in coaxial relationship thereto. Magnet 10 covers about one axial half or end of the coil-core structure, magnet 11 covers most of the other half or end and element 12 serves as axial spacer for the magnets on the center of the coil-core structure.

The two permanent magnets 10 and 11 are axially magnetized in relation to the tube axis, so that their resultant magnetic axis actually coincides with the magnetic axis of the coil-core structure. Magnets 10 and 11 are positioned so that their axial magnetization has opposite orientation, i.e., in the drawing, the two south poles of the two magnets face each other, around the periphery of coil 8 and within the area defined by the soft-iron ring 12. Two pole shoes 13 and 14- are magnetically coupled resectively to the axial end portions of the core 8, and the construction may be such that apertures in the pole shoes receive the core to support same. In addition, the two pole shoes are magnetically coupled to the two north poles of magnets 10 and 11.

The soft-iron spacer 12 is provided with a protrusion 15 serving as support and bearing for rocking armature 16. Hence, the permanent magnets do not serve as support for the armature. Moreover, as far as construction is concerned the entire mass for thepermanent magnet is not interposed between the coil-core structure, on one hand, and the pole shoe-armature arrangement, .on the other hand. As can be seen from FIGS. 2 and 3, the permanent magnets have overall outer configuration of a parallelepiped. Particularly, the magnets do not have to have cylindrical outer surface. A more favorable packaging is obtained by using a square-shaped outer contour. Here particularly corner space can be used as region to be occupied by the permanently magnetized material, so that a very favorable mass distribution of the material needed to provide suflicient pole strength of a permanent magnet can be obtained. This, in turn, means that in certain areas the wall thickness, shown at a, could be thinner than in case a permanent magnet had inner and out r yl n rical surfaces. In other words, the square of the cross section has sides the length of which can be shorter than the diameter of a cylindrical magnet of similar pole strength.

The cross sectional profile of the soft-iron ring 12 is similar to the one of the permanent magnets, i.e., it is not a true ring but the outer configuration is a square, except that the bearing 15 protrudes from that squareshaped profile. It should be mentioned that the relay could be supplemented in that the armature 16 could be provided with a recoiling spring to provide a polarized relay. In case of an unenergized state, as far as the coilcore structure is concerned, the armature will always assume a particular position.

The relay operates basically as the one shown in FIG. 1, but without having the disadvantages outlined above, particularly with regard to long term deteriorationof performance. The construction shown in FIG. 2 has the particular advantage that the pivot point of the armature is not any more in the immediate vicinity of a pole of a permanent magnet, but is separated from the closest pole, in this case from the two south poles of permanent magnets and 11, through the soft-iron of support 15. The two permanent magnets 10 and 12 are symmetrically positioned to each other and, for example, in relation to a plane 17 running through the pivot axis 18 of armature 16. A magnetic field as provided by core 8 upon energization of coil 9 (or one thereof) is asymmetrically superimposed upon the magnetic fields as provided by the two magnets, to reinforce one and to oppose the other. The magnetic connection and flux paths run through the soft-iron bearing of member 12 which closes the flux paths to one of the permanent magnets while opposing the flux lines emanating from the other. As there are relatively broad interfaces between the magnets and the ring-shaped member 12, there is no demagnetizing flux concentration at the poles of either magnet. This concentration in the pivot areas involves soft-iron and has, by definition, no lasting, permanent effect. Moreover, the two magnets are similar and each has a symmetrical pole construction which is beneficial as to utilization and effect of the magnetic fields they provide.

The symmetric construction of each magnet improves utilization of the available magnetism as provided by the permanently magnetized material. The permanent magnets are, furthermore, constructed in that the resultant magnetic axis is also an axis of symmetry. This has definite advantages as far as making the permanent magnet is concerned, as the construction lends itself directly to have that axis of symmetry directly as axis of preferred (and final) magnetization.

In order to completely utilize the advantageous configuration of the magnet, the soft-iron spacer 12 should be formed from sheet metal having a thickness which is determined by the magnetic flux to be conducted by the spacer and preventing particularly that the two magnets demagnetize each other. It is desirable that the surface area of the spacer in face to face contact with the magnets agrees with the profile of the permanent magnet, as illustrated, to make full use of the pole strength of the magnets. The projecting support '15 for the rocking armature is no exception to the latter rule, as the flux is diverted in the spacer in direction of outward extension of the bearing 15.

FIG. 4 illustrates an improved construction in accordance with the preferred embodiment of the present invention. The elongated cylindrical coil-core structure includes here a core 20 and a coil 21. This structure is essentially similar to those previously described. Also, this coil-core structure may include more than one coil for energizing the core through control currents in different circuits. The magnetic bias for this system includes also two permanent magnets 22, 23 and a soft-iron spacer 2-9, but they are of different construction.

The two permanent magnets 22 and 23 provide two axially aligned beds, each defined by cylindrically concave channels, such as channel 24 of magnet 22, and channel 25 of magnet 23, each having a semicircular profile for matchingly receiving the coil-core structure. The coil-core structure thus rests in these two axially aligned permanent magnet beds 22 and 23 as defined by surfaces 24 and 25 respectively. As can be seen more fully from FIG. 5, the cylindrical bed contour 25 of magnet 23 establishes a bottom portion merging into upwardly extending walls 27.

The axial end faces of the coil-core structure are in abutment respectively with pole shoes 30 and 31. The pole shoes each have a cross piece, such as 32 of pole shoe 30, in magnetical conductive engagement with the permanent magnets at their respective axial front faces. Each pole shoe has a tongue, such as 34 of pole shoe 30, in magnetically coupling relationship to core 20 at one respective end thereof. Each pole shoe has a pair of pole shoe tip elements such as 36 and 38 of pole shoe 30, and 35 and 37 of pole shoe 31.

The two permanent magnets 22 and 23 are polarized so that similar poles face each other in axial direction as far as the cylindrical concave contour of the beds and the axis of the coil-core structure is concerned. The two facing end portions of the two permaent magnets 22 and 23 are separated and magnetically coupled to the softiron element 29 which has a circular opening for receiving the central portion of the coil-core structure.

The upper side 39 of spacer 29 serves as a support for an armature 40. Armature 40 has two arms 41 and 42 extending in symmetric relation to a crosswise extending groove 49 with which armature 40 rides atop surface 39 of spacer 29 to establish a two arm rocking lever-type armature. The arms 41 and 42 respectively have concave, cylindrical indentations 43 and 44, facing down. Each of these cylindrical indentations has somewhat matching contour as far as the cylindrical shape of the coil-core structure is concerned. However, the axes for the cylinders defining respectively the contour of the indentations or channels 43 and 44 are inclined by an angle which is equal to the angular range for rocking of armature 40. Arm 41 specifically has a top portion from which extend side walls 45 to establish the concave down surface 43.

In the position of armature 40 illustrated in FIG. 4 and FIG. 5, the two bottom faces 47 of side walls 45 respectively rest on pole shoe tips 35 and 37 to define one of the stationary positions of armature 40. This permits specifically observance that armature 40 extends on the top of the coil-core structure, so that the arm, here 41, which is down, extends along the side and in downward direction, enveloping that half of the coil-core structure so that in conjunction with permanent magnet 23, the coilcore structure is essentially enveloped along the cylindrical periphery thereof with the exception of the small space equal to the vertical height of pole shoe tips 35 and 37. The other arm, 42, is of symmetrical construction, but in the illustrated position it extends somewhat up. The bottom surfaces 48 of wall portion 46 of arm 42 specifically show that angle in relation to the bottom surfaces 47 of arm 41 due to the fact the axes of the cylinders defining indentations 43 and 44 are inclined by that angle. To state it difierently, the two semicylindrical indentations 43 and 44 of armature 40 are not coaxial but they are angularly oriented to each other so that in either one of the two possible stationary positions of the armature, always one arm is essentially axis parallel, almost coaxial, with the coil-core structure and the respective permanent magnet bed thereunder.

The particular advantage of this relay construction is to be seen in that the permanent magnets providing the magnetic bias and the rocking armature together define an enclosure having overall cylindrical configuration to enclose the cylindrical coil-core structure of the energizing system of the relay whereby any deviation from complete enclosure comes only as the result of the requirements (1), that .there mustbe provided a certain range permitting rocking in a plane running through and including the magnetic axes of the system; and (2), that spacing (pole shoe tips 35, 37, etc.,) is needed to prevent sticking of the armature to one of the permanent magnets.

The cross sectional profile, particularly of the permanent magnet beds, is circular, as stated, but that profile could also be U-shaped or it could be more than a semicircle, in which case there would be a narrower armature; the pole shoe tips could be placed to extend axially from the tongues of the pole shoes. One can see that as far as overall size reduction is concerned, the embodiment shown in FIGS. 4 and 5, is a step further toward a more compact design, as compared with the prior art construction shown in FIG. 1 or the first embodiment of the invention shown in FIGS. 2 and 3, whereby all of the advantages outlinedv above, with regard to the embodiment of FIG. 2, are equally valid for the embodiment shown in FIG. 4. This is particularly so with regard to flux concentration areas and symmetry of the design for each of the permanent magnets. Moreover, the compactness of the construction is aided by the fact that the magnets themselves are more compact and have contour to complement the contour of the armature so that the core-coil structure is located between them. The relay actuator arms are positioned to extend generally in a direction parallel to the rocking axis. Also, this embodiment of the invention could be supplemented by a recoiling spring in order to establish therewith a polarized relay.

The embodiment of the invention shown in FIG. 6, is a simplified version of the construction of FIGS. 4 and 5. The permanent magnets 51 and 52 have cylindrical beds with relatively high side walls to extend around the coil-core structure having core 50 and coil 53. The magnets partially envelop the coil-core structure along the cylindrical periphery thereof and to a significant degree. The two magnets again have oppositely oriented magnetic axes and two similar poles face each other through soft-iron member 54, separating the magnets and serving as armature bearing and support. The ends of the coilcore structure, particularly of core 50, as Well as the respective other magnet poles are coupled to simply constructed pole pieces 56 and 57, extending somewhat higher than the side walls of magnets 51 and 52.

The armature 60 is constructed of two similar plates '61 and 62 joined at an angle along surfaces defining the line 63. The simplified construction results particularly from overall flatness of the armature plates, particularly as to their downward directed surfaces. The side walls of the magnets may extend rather high, leaving just a narrow gap between them, and the respective one of the armature plates rests on the adjoining pole shoe to prevent sticking of that armature plate to permanent mag- Y netic material, not subject to demagnetization upon energization of the coil-core structure.

It was found that the inner wall surfaces of the permanent magnet do not have to match completely the contour of the coil-core structure all around as the armature does not have to be shielded from the coil by permanent magnetic material. In dependence upon the type of magnetic material employed, the forms of the magnets 51 and 52 can be such to leave a larger gap between them and the armature so that the coil is not completely enclosed. It should be noted further that the plates 61 and 62 could be somewhat bent individually and as a whole, and about an axis transverse to line 63, as well as to the normal on the respective plate, to obtain some profile matching as between the upwardly directed cylindrical surface of the coil-core structure and the downwardly directed surface of the plates. This is considerably simpler than machining a cylindrical contour into the armature, as is necessary in the embodiment of FIGS. 4 and 5.

The invention is not limited to the embodiments described above, but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be covered by the following claims.

I claim:

1. A relay having an axial oriented coil-core structure, which includes a core and at least one coil on the core, comprising:

a pair of permanent magnets spaced axially along the coil-core structure, each at least partially enveloping a portion of the coil-core structure;

the magnets having their magnetic poles oriented so that two similar poles face each other at the coilcore structure along said axial orientation;

:1 soft-iron member separating the two magnets and being magnetically coupled to each of them at said two similar magnetic poles;

at two arm rocking armature pivotally mounted on the member for rocking about an axis transverse to the axial orientation direction; and

means including rocking motion limiting means for magnetically coupling the core-coil structure and the other poles of the magnets to the armature and engaging one or the other arm of the armature, depending upon the position of the armature and on the combined magnetic attraction provided by the coilcore structure and by the permanent magnets.

2. A relay as set forth in claim 1, the two permanent magnets each having an inner, at least essentially cylindrical surface for receiving different portions of the coil-core structure as spaced apart along the axis thereof, the magnets having similar outer cross sectional profiles, the permanent magnets being axially magnetized.

3. A relay as set forth in claim 2, the two permanent magnets having outer contour of a parallelepiped.

4. A relay as set forth in claim 1, the soft-iron member having a cylindrically-shaped opening for receiving the coil-core structure and axially separating from each other but being coupled to the two permanent magnets.

5. A relay as set forth in claim 1, the outer profile of the soft-iron member matching that of the two permanent magnets but having an extremity serving as rocking bearing for the armature.

6. A relay as set forth in claim 1, the two permanent magnets having indentations, profiled to receive the coilcore structure and forming a support bed and having laterally upwardly extending side walls, the inner surfaces thereof forming part of the bed;

the coil-core structure as upwardly exposed being at least partially covered by the armature thereabove.

7. A relay as set forth in claim 6, the armature having two arms having concave down surfaces to serve as cover for the coil-core structure and having portions extending laterally down along the sides of the coil-core structure, toward the upwardly extending side walls of the permanent magnet bed so that armature and magnets essentially envelop the coil-core structure along its axial extension.

8. A relay as set forth in claim 7, the concave down surfaces of the arms of the armature as individually matching the upward extending contour of the core-coil structure being inclined in an axial plane transverse to the axis.

9. A relay as set forth in claim 1, the armature having symmetric construction in relation to the rocking axis.

10. A'relay as set forth in claim 9, the armature constructed so that the surfaces of the two arms facing toward the coil-core structure are oriented at an angle to .each other in an axial plane transverse to the rocking axis.

11. A relay as set forth in claim 10, the armature constructed from two joint inclined plates for rocking about an axis in a plane along which the plates are joined.

12. A relay as set forth in claim 9, the arms of the armature having respectively two inclined, concavely profiled surfaces inclined to each other at an angle in a plane transverse to the rocking axis, for one or the other to respectively cover the portion of the coil-core structure as projecting upwardly from one and the other of the two permanent magnet beds and respectively upon completed attraction of the respective arms.

13. A relay as set forth in claim 1, and including resilient means coupled to the armature to force the armature into a particular position upon de-energization of the coil of the coil-core structure.

14. A relay as set forth in claim 1, there being actuating means coupled to the armature and extending predominantly in the direction of the rocking angle hereof.

15. A relay as set forth in claim 1, the magnetic coupling means constructed to provide embedding of the coilcore structure at its axial end faces.

16. In a relay, the combination comprising:

an axially oriented coil-core structure;

a pair of axially spaced, similar permanent magnets having oppositely oriented magnetization with coaxial magnetic axes extending parallel to the axis of the coil-core structure;

a two arm rocking armature, armature and magnets positioned and having contour to receive the coilcore structure between them so that armature, the magnets and the coil-core structure extend generally parallel to each other along the axis of the coil-core structure; and

soft iron means coupled to facing similar poles of the magnets, having an aperture to receive the coil-core structure, and providing support and bearing for the armature for rocking over a limited angular range about an axis transverse to the coil-core axis, for the arms of the armature to rock back and forth in relation to the axial ends of the coil-core structure.

17. In the combination set forth in claim 16, the magnets each have similar pole construction.

18. A relay having an axially oriented coil-core structure, a pair of pole shoe means respectively coupled to the two axial ends of the coil-core structure, permanent magnet means for particularly biasing the pole shoes, and a two arm rocking armature for selective engagement with one or the other of the pole shoe means, the improvement comprising:

a pair of permanent magnets as the permanent magnet means positioned to have oppositely oriented magnetization parallel to the axis of the coil-core 10 structure, and being disposed at least partially on and along one side of the coil-core structure;

a soft-iron spacer separating the two magnets and being coupled to two similar poles thereof facing each other through the spacer, the soft-iron spacer constructed to serve as hearing and support of the armature on the side opposite to the one side of the coilcore structure.

19. A relay as set forth in claim 13, the permanent magnets both being on the one side only and having concave contour in planes transverse to their respective magnetic axes matching convex contour of the coil-core structure as juxtaposed.

20. In a relay construction, a coil-core arrangement having a particular axis for magnetization and extending along the axis;

a pair of permanent magnets arranged symmetrically to each other in axis parallel relationship to the axis of the coil-core arrangement, a pair of similar poles of the magnets of the pair facing each other; each of the magnets at least partially enveloping an axial end section of the coil-core arrangement, so that portions of the magnets are not located directly in the space between the coil-core arrangement and the armature;

a soft-iron member interposed between the magnets and having broad interface magnetic contact with each of the two similar poles;

a pair of pole shoe means respectively coupled to the two axial ends of the coil-core arrangement as well as the respective other poles of the magnets; and

an armature pivotally supported on the soft-iron member for rocking between position of engagement with one or the other of the pole shoe means in dependence upon energization of the coil of the coil-core arrangement.

References Cited UNITED STATES PATENTS 2,941,130 6/1960 Fischer et al. 335230 3,317,871 5/1967 Adams 335-230 FOREIGN PATENTS 881,059 6/1953 Germany 335-230 1,469,247 1/1967 France 335-229 GEORGE HARRIS, Primary Examiner US. Cl. X.R. 335-230 

